Unit 3 ch. 7 vocab

Cellular Respiration, Fermentation

Fermentation

Fermentation

A catabolic process that makes a limited amount of ATP from glucose (or other organic molecules) without an electron transport chain and that produces a characteristic end product, such as ethyl alcohol or lactic acid.

Aerobic Respiration

A catabolic pathway for organic molecules, using oxygen (O2) as the final electron acceptor in a electron transport chain and ultimately producing ATP. This is the most efficient catabolic pathway and is carried out in most eukaryotic cells and many prokaryotic organisms.

Cellular respiration

The catabolic pathways of aerobic and anaerobic respiration, which break down organic molecules and use an electron transport chain for the production of ATP.

Redox reactions

A chemical reaction involving the complete or partial action involving the complete or partial transfer of one or more electrons from one reactant to another; short for reduction-oxidation reaction.

Oxidation

The complete or partial loss of electrons from a substance involved in a redox reaction.

Reduction

The complete or partial addition of electrons to a substance involved in redox reaction.

Reducing Agent

The electron donor in a redox reaction.

Oxidizing agent

The electron acceptor in a redox reaction.

NAD+

Nicotinamide adenine dinucleotide, a coenzyme that cycles easily between oxidized (NAD+) and reduced (NADH) states, thus acting as a electron carrier.

Electron transport chain

A sequence of electron carrier molecules (membrane proteins) that shuttle electrons down a series of redox reactions that release energy used to make ATP.

Glycolysis

A series of reactions that ultimately splits glucose into pyruvate. Glycolysis occurs in almost all living cells, serving as the starting point for fermentation or cellular respiration.

Citric acid cycle

A chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecules begun in glycolysis by oxidizing acetyl CoA (derived from pyruvate) to carbon dioxide; occurs within the mitochondria in eukaryotic cells and in the cytosol of prokaryotes; together with pyruvate oxidation, the second major stage in cellular respiration.

Oxidative phsophorylation

The production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration.

Substrate-level phosphorylation

The reactant on which an enzyme works.

Acetyl CoA

Acetyl coenzyme A; the entry compound for the citric acid cycle in cellular respiration, formed from a two-carbon fragment of pyruvate attached to a coenzyme.

ATP synthase

A complex of several membrane proteins that functions in chemiosmosis with a adjacent electron transport chains, using the energy of a hydrogen ion (poroton) concentration gradient to make ATP. ATP synthases are found in the inner mitochondrial membranes of eukaryotic cells and in the plasma membranes of prokaryotes.

Chemisosmosis

An energy-coupling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work, such as the synthesis of ATp. Under aerobic conditions, most ATP synthesis in cells occurs by chemiosmosis.

Proton-motive force

The potential energy stored in the form of a proton electrochemical gradient, generated by the pumping of hydrogen ions (H+)across a biological membrane during chemiosmosis.

Alcohol fermentation

Glycolysis followed by the reduction of pyruvate to ethyl alcohol, regeneration NAD+ and releasing carbon dioxide.

Lactic acid fermentation

Glycolysis followed by the reduction of pyruvate to lactate, regenerating NAD+ with no release of carbon dioxide.

Obligate anaerobes

An organism that only carries out fermentation or anaerobic respiration. Such organisms cannot use oxygen and in fact may be poisoned by it.

Facultative anaerobes

An organism that makes ATp by aerobic respiration if oxygen is present but that switched to anaerobic respiration or fermentation if oxygen is not present.

Anaerobic Respiration

A catabolic pathway in which inorganic molecules other than oxygen accept electrons at the “downhill” end of electron transport chain.